Date of Award
Bachelor of Science
Cindy S. Ticknor
Carotenoids are naturally occurring, fat-soluble pigments that play an important role in the embryonic development of songbirds. Female songbirds use different strategies to allocate these important maternal resources to their eggs. Little research has been done on whether North American songbirds exhibit laying sequence patterns in their allocation of carotenoids. We studied the laying-sequence variation in yolk carotenoids and egg metrics of nine full clutches of Eastern Bluebirds (Sialia sialis) in Columbus, Georgia. I predicted that Eastern Bluebirds would exhibit a brood reduction strategy, with the first-laid eggs containing a higher concentration of carotenoids than the last-laid eggs. I also predicted that the egg mass and size would remain consistent across the clutch due to an increase in secondary resources across the clutch. My results indicated that Eastern Bluebirds did not follow a brood reduction strategy but rather had unpredictable varying carotenoid concentrations across the clutch. I found five carotenoids in the egg yolks of Eastern Bluebirds: lutein, β-carotene, zeaxanthin, astaxanthin, and β-cryptoxanthin. As predicted, the egg mass, egg length, and egg width did not vary significantly across the clutch.
Barkhouse, Jessica, "Laying-Sequence Variation in Yolk Carotenoids of Eastern Bluebirds" (2020). Theses and Dissertations. 381.